Monday, November 10, 2014

Welcome to the forty-fifth issue of LLVM Weekly, a weekly newsletter
(published every Monday) covering developments in LLVM, Clang, and related
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James Molloy has been experimenting with the scheduling model on the
Cortex-A57 and found some
oddities. I
noted the MicroOpBufferSize is currently set to 128, and reducing it right
down to 2 seems to have no effect. Andrew Trick responded with some suggetions
on implementing a custom scheduling
strategy.

LLVM commits

The PBQP register allocator has had its spill costs and coalescing benefits
tweaked. This apparently results in a few percent improvement on benchmarks
such as EEMBC and SPEC. r221292,
r221293.

The new SymbolRewriter pass is an IR to IR transformation allowing
adjustment of symbols during compilation. It is intended to be used for symbol
interpositioning in sanitizers and performance analysis tools.
r221548.